Methods and compositions for inhibiting CD32b expressing cells

摘要

The invention relates to an immunoglobulin that has (a) enhanced binding affinity to FcgammaRlIb and reduced binding affinity for FcgammaRIIIa relative to a parent antibody; (b) binds FcgammaRlIb with a Kd of less than about 100 nM and (c) coengages a target antigen and FcgammaRlIb on the cell surface. The invention also relates to methods of inhibiting a cell comprising contacting the cell with an immunoglobulin, wherein the immunoglobulin (a) binds FcgammaRlIb with a Kd of less than about 100 nM and coengages a target antigen and FcgammaRlIb on the cell surface; (b) has enhanced binding affinity to FcgammaRlIb and reduced binding affinity for FcgammaRIIIa relative to a parent antibody, and coengages a target antigen and FcgammaRlIb on the cell surface; or (c) has enhanced binding affinity to FcgammaRlIb relative to a parent immunoglobulin, coengages CD19 and FcyRIIb on the cell surface, and wherein the cell is a B-cell.